i've used a weber mass lite power attenuator with my 60w mesa boogie markIIb head for almost 10 years now.
works great.
combined with a palmer pdi-09, i can do direct recording in the middle of the night,
with the attenuator maxed out,
but taking the full output off the amp thru the palmer first,
getting the full power output of the amp as if it were not attenuated,
then running the thru of the palmer into the attenuator, for monitoring at any volume i want.
any recordings you've heard from me in the last 10 years has been mostly the palmer.
the weber is just to control monitor volume.
for the purists, buying a low wattage amp for low volume recording is the best,
having a great master volume is second best,
attenuator on large wattage amp for volume control is 3rd.
but you'll never get the sound of big iron, using an attenuator, playing at low volume,
and not moving some air.